The ESL has provided the analysis of steroids and other hormones in samples of biological interest to ORPRC investigators for the past 20 years. The laboratory originated in the Division of Reproductive Biology in 1973; a portion of the facility was included in a NICHD P50 specialized center in 1979 and was one of four cores in a NICHD P30 population center in 1984. The NICHD Center grant has supported a portion of the Laboratory Director's position and has supported fully two or more research assistants and a part-time laboratory aide. The Primate Center core has provided the remainder of the Director's salary and additional support for research assistants was obtained sporadically from nonfederal sources. The current ESL program contains both service and research functions and provides the resources, assays and structural flexibility to allow Primate Center core investigators, Population Center approved investigators, and Institutional collaborators access to services. The service functions include provision of routine steroid assays for most naturally occurring, as well as a variety of synthetic androgens, corticoids, estrogens or progestins, the analysis of protein hormones of reproductive interest and the determination of a limited number of prostaglandins. Among the specialized assays that the laboratory provides are rapid assays (results available withIn 1-3 hrs) for, identification of experimental subject's physiological status and catecholamine assays for various neurotransmitters. Between 15 and 20,000 samples a year were processed during each of the past five years for investigators at the ORPRC, OHSU, or 19 other universities, three other Primate Centers, and four pharmaceutical firms. Other service efforts are directed toward enhancing the production and use of the Primate Center's indoor breeding colony, maintaining the Center's isotope use license and coordinating the employee serum bank. The research functions of this laboratory include: collaboration with various Center and extramural research programs in reproduction; interactions with pharmaceutical and biotechnology firms in projects that utilize nonhuman primates for nonterminal reproductive toxicology or risk assessment; and assay acquisition and development for Center scientists.